Bi-Directional Links
A two-way link between files or pages.
A typical hyperlink on the Internet is a one-way link. I can link to another website, but the other website does not know that I linked to it. It is "unaware".
An "aware" link, or Bi-Directional Link is a two-way link. When I link to another page, it knows that I linked to it, enabling a user to go back and forth between the pages.
The Internet does not, by default enable bi-directional links. Digital Gardens typically do. Obsidian is a note-taking app that enables bi-directional links by default, opening up non-linear note-taking.
See more in this article on bi-directional links by Maggie Appleton or my thoughts onSmart Note Taking.